Production of levulinic and homologous acids and intermediate compounds from dihalogen butenes



Patented Mar. 5, 1940 UNITED STATES PATENT OFFICE.

Donald D. Coflman, Lindamere, and Arnold M.

Collins, Wilmington,

Del., assignors to E. I.

du Pont do Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application August/14, 1936, Serial No. 96.050

22 Claims. (Cl. 260-486) This invention relates to the synthesis of levulinic acid from certain dihalogenbutenes, to in termediate compounds formed in this synthesis, and to their preparation.

6 Levullnic acid is a well-known compound which has a number of uses. It is generally derived from sugars (hexoses) by long boiling with dilute mineral acids; it may also be synthesized by reacting chloracetic ester with the sodium derivative of acetoacetic ester and hydrolyzing the resulting product. These methods are unsatisfactory in that the latter is expensive and the former results in an impure product.

It is an object of this invention to provide a new process for the preparation of levulinic acid and homologues of levulinic acid. A further object is to prepare levuiinic acid from dihalogenbutenes. A still further object is to prepare and isolate intermediate compounds formed in the synthesis of levulinic acid from dihalogenbutenes.

Other objects will appear hereinafter.

These objects areaccomplished by converting a dihalogen-2,4-butene-2 into a haiogen-2-cyano- 4-butene-2 by treatment with a soluble and ionizable cyanide such as an alkali cyanide, hydrolyzing the halogen-2-cyano-4-butene-2 to a halogen-2-pentene-3-oic acid, treating the halogen- 2-pentene-3-oic acid with a strong non-oxidizing oxygen acid, such as sulfuric acid, and hydrolyzing the resultant product to levulinlc acid..

In the preferred embodiment of the invention, dichloro-2,4-butene-2 is reacted with sodium cyanide in alcoholic solution. The resulting chloro- 2-cyano-4-butene-2 is then hydrolyzed, under the influence of concentrated hydrochloric acid, to chloro-4-pentene-3-oic acid. The latter acid on treatment with concentrated sulfuric acid, followed by hydrolysis, is readily converted to levulinic acid. The intermediate chloro-4-pentene- 3-oic acid may be more fully identified by two of its derivatives, the ethyl ester and the anilide.

Details of a typical method for converting a dihalogen-2,4-butene-2 to ievulinic acid, via the aforesaid intermediate products,,are as follows.

It will be understood that these specific details are illustrative and not limitative.

Into aqueous ethanol (160 cc. of ethanol to '10 cc. of water) was introduced 125 g. (1 mole) of dichloro-2,4-butene-2 and 49 g. (1 mole) of sodi- 50 um cyanide. The reaction mixture was gently refluxed for 4 hours after which it was poured into cold water, washed, separated and dried with anhydrous potassium carbonate. By fractionation there was obtained a 57% yield (66 g.) of

chloro-2-cyano4-but2ne-2, the compound being identified by analysis for nitrogen (calculated 12.10%, round 11.8%). This compound had the following properties: B. P. 81-83 C./18 mm.;

and Ma 29.74 (Ma ca1c.=29.54).

A mixture of 133 g. (1.1 mole) of chloro-2-cyano-4-butene-2 with 200 cc. of 37% hydrochloric acid was refluxed for one hour. The reaction mixture was then cooled to room temperature, extracted with ether, and the ether extract fractionated. There was obtained a 78% yield (105 gm.) of chloro-4-pentene-3-oic acid, the compound bei'ng identified by a carbon and hydrogen analysis and by determination of its neutralization equivalent. (Calcd. for C5H1O2Cl2C, 44.61%; H, 5.20%: neutralization equivalent, 134.5. Foundi C, 44.78%; H, 5.25%; neutralization equivalent, 135.5.) This acid had the following properties: B. P. 83 85 C./1 mm.; M. P. 1'7-l8 C.;

Ma 31.29 (Ma calc.=31.34). Chloro-4-pentene- 3- oic. acid may be further characterized by its ethyl ester (B. P. 81-83 0.715 mm.;

and by its anilide (M. P. 101 C.). The ester is made by heating 30 gm. of the acid at C.

acid prepared as above was added slowly with cooling 100 g. of concentrated sulfuric acid. Hydrogen chloride was rapidly evolved and after standing at room temperature during five hours, the reaction mixture was poured onto 300 g. of crushed ice. The solution obtained was subjected to continuous ether extraction, the extract being carefully dried with anhydrous magnesium sulfate. After removal of the ether, 15 g. of material was received from which by distillation there was obtained a 36% yield (10 g.) of levulinic acid, which was identified by its boiling point of 103- 106 C./1 mm.; by its melting point of 31-3-3 C., by its neutralization equivalent of 118 (calcd. 116), and by an elementary analysis which gave 51.33% carbon and 7.24% hydrogen as compared to calculated values of 51.72% and 6.90% respecproportions of reactants and solvents, and methtively. ods of isolation and puriflcations, may differ The invention is illustrated in the above spewidely from those given in the preferred emciflc description-b pplying it to dichloro-. 2,i;buwithout exc eding the scope of 6 tene-2T-but' as ha en stated other ,dihalog'en- I 2,4-butenes-2 may be likewise employed; "Sin'iiarigetieto advanlarly, homologues of these dihalogenbutenes,.such vP W n o her reactants are used. The P as those corresponding to the f ula 'tipal limits of such variations as well as suitable odification he procedure given above will Br i I U ose skilled in the art. Simi-. in which-X and X are halogen-and a'rl y, thew uctantsmay be brought together at Y carbon radical and those .corgspondingt once oron may be added slowly to the other}; formula CH3C(X)=C(B);,GQ ;'J (R' H W H I, (1 may. in molar proportions of with X and X are halogen and;R and Rf arehydro= cess e gen or hydrocarbon radicals but are neveriilboth v v amides of the halogen-4- 15 hydrogen, may be used. The halogenatoms may pentene-B 7 ris, for example, chloro-4-p'enbe chlorine, bromine or iodine and while spr e'f t'ene-3-oic acidy may be made. All esters "and ably the same, they may be diiferentf 'specific amides of these acids are included within the dihalogenbutenes which may be employediin the ;;scope o f.-tl1e present invention. Theymay be present invention are dichlor,o 2,$ butene;2, diprepared f rom the acids by the methods dis- 2o repared directlyraifrom' halogen-2 cyano-4-but e 2 for'aexample, hlotene-2. i The dihalogenbutenes may be prepared as de- 85 scribed in a copen ingsappliii fi qnsz0 Ga gothers" 2-c yfanfo- 4-bu'tene-2 by-1 seating. theanitrlle and Collins, Serial 'No 688,030, file resenceizofiz zcatalyst 2,1933. Similarly by-fthe addition,oi ahyd qgen" y y fn' fld .halogenbutadienes describedin Jacob with: methyl, lepropylmiso V 80 Patent 1,950,440wand carothersgaan Y F Y fi p y 'e'cy li so n'd -phenylet'hyl' i alcoholsso with 1 phenols,.such" as phen01;icreso1;.a anmxmen nma be made. Simil'a y r'amidesgiof these! acids-Finlay be prepared by"'reacting ithe" 'cid ,f'Ql aits;halid ith am'moniaa or 'u'tyl-,' and laury the homologues .fof the -..-;dihalogenbu scribed above.-, ln ugeneral,homologou cine; :sarcosine, et toi-mentioni-he ie 11.1585

eidkane M ew 40 app aproduce the nitrile'l iri'steadzofithe;sodium cyanide of the above illustration we may use, for example, the cyanide of lithium, ammonium;

. potassium, or calcium. ..{Ihe ea ion i preferrial a readily available; derivative "ably carriedarout'in a liquid ene. It' -ha'siialrea'dyi been pointed: ut hat the i on djh'aldgenbut'e'negand-g th y i process is en-ti-rely new.--'and-.'='fur'rushes z m y use co s or ke tones i wo new ah'd valuablefintermediates:-

' presentrprocess; permit moreof' thes'e respectsu-e It is apparent-that'many widel di-fi" en em- 'odiment'smf; thiseinvehtio madazwith- :thereof reliminary isolation; a correspondingyhalogen car esiredvrrnethod, of hydr a and, .therefore iiitl Iexcept asaindicate We clai wa-actlng ae-strong non -ok-idizl billet se 11101031168 and .1 uimay be ,facilitateqbyin rodu'cnofibr ata-lyst;usuchas. yygng; It' istmbezund StQQQof courseQthat v itions under.whiclntheiabovepr ctsfare pre which i'n vol'v u acid ting: Iva s dihalQgen-ZA- 76 pared, such as temperature, "tin' i' z 0f heating?"*butene-Zirit i halogehficyanto-Awbutene+2,

ns given'in 5 amazes then converting the halogen-2-cyano-4-butens-2 into a halogen-4-pentene-3-oic acid, the step which comprises reacting sulfuric acid with a halogen-4-pentene-3-oic acid and then hydrolyzing the resultant product. I

4. In a process for producing levulinic acid which involves converting dichloro2,4-butene-2 into chloro-2-cyano-4-butene-2, then converting the chloro-2-cyano-4-butene-2 into chloro-4- pentene-3-oic acid, the step which comprises reacting sulfuric acid and chloro-4-pentene-3- oic. acid, and then hydrolyzing the resultant product.

5. The process which comprises reacting a member of the group consisting of the dihalogen-2,4-butenes-2 and their homologues with a soluble and ionizable cyanide, hydrolyzing the resulting member of the group consisting of halogen-2-cyano-4butenes-2 and their homolo -ues to a member of the group consisting of halogen-4-pentene-3-oic acids and their homologues, reacting a strong'non-oxidizingoxygen acid with the'halogen acid thus obtained, and

' hydrolyzing the resultant product to a member of the group consisting of levulinic acid and its homologues.

6. The process which comprises reacting a diha1ogen-2,4-butene-2 with a soluble and ionizable cyanide in the presence of a solvent for the butene and the cyanide, hydrolyzing'the resulting halogen-2-cyano-4-butene-2 to a halogen- 4-pentene-3-oic acid, reacting a strong non-oxidizing oxygen acid with the halogen-4-pentene- 3-oic acid, and hydrolyzing the resultant product to levulinic acid.

7. The process which comprises reacting dichloro-2,4-butene-2 with an alkali cyanide, hydrolyzing the resulting chloro-2-cyano-4- butene-2 to chloro-4-pentene-3-oic acid, reacting sulfuric acid with the chloro-4-pentene-3-oic acid, and hydrolyzing, the resultant product to levulinic acid.

8. The process of claim 2 further characterized in that the sulfuric acid addition takes place in the presence of a mercuric salt catalyst.

9. The process of claim 6 further characterized in that the halogen-2-cyano-4-butene-2 is hydrolyzed by treating it with an alkaline saponifying agent, 1 i

10. The process which comprises reacting dichloro-2,4-butene-2 with sodium cyanide in the presence of a solvent for the reactants, converting the chloro?2-cyano-4-butene-2 so formed to chloro-4-pentene-3-oic acid by treatment with hydrochloric acid, reacting the chloro-4-pentene- 3-oic acid with sulfuric acid and hydrolyzing the resultant product to levulinic acid.

11. A compound of the general formula in which X is;halogen and Y is a member of the group consisting of hydrogen and'alcoholic radicals.

12. A halogen-4-pentene-3-oic acid.

13. Chloro-4-pentene-3-oic acid.

14. An ester of a halogen-4-pentene-3-oic acid.

15. An ester of chloro-4-pentene-3-o1c acid.

16. The process which comprises reacting a member of the group'consisting of the dihalogen- 2,4-butenes-2 and their homologues with a soluble and ionizable cyanide, and then hydrolyzing the resulting member of the group consisting of haIogen-Z-cyano-4-butenes-2 and their homologues to a member of the group consisting of halogen-4-pentene-3-oic acids and their homologues.

17. The process of claim 6 further characterized in that'the halogen-2-cyano-4-butene-2 is hydrolyzed by treating it with a mineral acid.

18. The process which comprises reacting dichloro-2,4-butene-2 with sodium cyanide in alcoholic solution, hydrolyzing the resulting chloro- 2-cyano-4-butene-2 with concentrated hydrochloric acid, reacting cencentrated sulfuric acid with the halogen acid thus obtained, and hydrolizing the resultant product tolevulinic acid.

19. In a process for producing levulinic acid, the step which comprises treating chloro-i-pentene-3-oic acid with concentrated sulfuric acid, and then hydrolyzing to produce levulinic acid.

20. The process of claim 6, further characterized in that the halogen-2-cyano-4-butene-2 is hydrolyzed by treating it with steam under pressure.

' 21. The process which comprises reacting a dihalogen-2,4-butene-2 with a soluble and ionizable cyanide and then hydrolyzing the resulting halogen-2-cyano-4-butene-2 to a halogen-4- 'pentene-3-oic acid.

22. The process which comprises reacting dichloro-2,4-butene-2 with a soluble and ionizable cyanide and then hydrolyzing the resulting chloro-2-cyano-4-butene-2 to chloro-i-pentene- 3-oic acid.

DONALD D. COFFM'AN. ARNOLD M. COLLINS. 

